1. Field of the Invention
The present invention relates generally to semiconductor devices and, more particularly, to a digital switching technique for detecting data on a semiconductor device, such as a memory device.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Microprocessor-controlled integrated circuits are used in a wide variety of applications. Such applications include personal computers, telephones, control systems, networks, and a host of consumer products. Microprocessors are essentially generic devices that perform specific functions under the control of a software program. This program is stored in a memory device, such as dynamic random access memories (DRAMs), static random access memories (SRAMs) or other suitable types of memories that are coupled to the microprocessor. Not only does the microprocessor access memory devices to retrieve program instructions, but it also stores and retrieves data created during the execution of the program in one or more memory devices. It should be understood that memory devices and microprocessor-controlled integrated circuits are typically mass produced through fabrication processes that form semiconductor chips.
In fabricating a semiconductor chip, different materials are layered together to form various structures or circuitry. These structures may enable the exchange of data signals between semiconductor chips and other devices. One structure that may be formed in the semiconductor chip is a signal switching structure that may be used to detect changes in data signals. These signal switching structures may be implemented in a variety of devices, such as DRAMs, SRAMs, memory buses, processors, network processors, application specific integrated circuits (ASICs), and intra-chip buses. As such, the signal switching structures may be utilized to enhance the operation of the device.
Constraints on cost, physical space and operating speeds continue to drive enhancements in the design of the signal switching structures in semiconductor devices. One signal switching design, which may be implemented, may utilize a data pin along with a complimentary data pin to provide data sensing. By utilizing two pins to detect data signals, this switching technique increases the overall cost of the semiconductor chips because of the additional pin that is used in detecting the data signal. An alternative signal switching design uses a single data pin along with a fixed reference voltage. Disadvantageously, this fixed reference signal switching technique operates slower, because the signal sensing depends on the crossing of a reference voltage. Another alternative signal switching design uses a single data pin along with two voltage timing reference (VTR) signals to provide faster sensing of changes in the data signal. This approach provides for faster data sensing because one of the VTR signals is complimentary to the data signal. However, it may have problems with feedback timing issues and may fail to provide symmetric signals. This means that the data sensing window, which is the voltage and time period that a receiver may detect the data signal, has to be larger to compensate for these problems. As such, each of the forgoing signal switching techniques has drawbacks associated therewith.
Due to the ever-increasing demands for smaller structures and faster data signal sensing, the processing of such signal switching structures is often costly and complex. Thus, providing higher performance data sensing structures that minimize the timing and symmetry issues would be advantageous.